Why is the LED lamp flashing and how to solve the problem?

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The flickering and flashing of LED lamps is not only unpleasant for the eyes, but also harmful. The reasons for the undesirable phenomenon lie both in the low quality of LED lamps and in the influence of external factors. In any case, it is important to find out the cause of the flicker and eliminate it.

Causes of flickering when the switch is on

If the LED lamp flickers immediately after switching on, then there is a problem in the wiring diagram. Among the common causes of LED flickering is poor-quality installation. If the contacts and circuit elements are not securely fixed, a variety of problems may occur during operation, including flickering.

When connecting the cable, take into account the polarity – according to the color marking of the wires. When installing lamps in older buildings, use a multimeter to determine the phase and neutral conductors. If the wiring is incorrect, there is a small amount of voltage in the circuit causing the lamp to flicker.

Flickering LED light

After switching on, LED lamps can not only flicker, but also burn brightly enough. If the LED lamp shines dimly, the first thing to do is to check the voltage level in the network by connecting another lamp to it.

Low voltage

To measure the voltage in the mains, use special measuring instruments – multimeters or voltmeters. If a value in the range of 215-225 V appears on the indicator / scale, then everything is in order. Deviations of 5 V are not critical.

Less than 200 V or more than 230 V indicate problems with the mains voltage and require a speedy solution. Contact the experts – in the housing office or an organization engaged in the maintenance of electrical networks. Specialists will measure and adjust the operation of the transformer at the substation.

If the repair team cannot ensure that the voltage meets the requirements of the PUE, it is necessary to include a current limiter or voltage stabilizer in the circuit.

Insufficient filtration efficiency

In cheap Chinese lamps, and sometimes domestic ones, a full-fledged driver is built on the basis of a simple circuit. How insufficient filtering efficiency causes flickering of the LED lamp:

  1. The driver has a diode bridge D1-D4. A smoothing capacitive filter C2 – Rf is connected in series with it. The input voltage is reduced to the desired value in the resistor-capacitor circuit (quenching resistor Rg and smoothing capacitor C1).
  2. The filter qualitatively eliminates the residual ripple of the current rectified by the diode bridge, if the network has a standard voltage. But the bridge cannot smooth out impulse noise, which causes flashing.
  3. At the slightest deviation of the input voltage from the specified values ​​- due to the steepness of the current-voltage characteristic – there are significant changes in current. This immediately affects the brightness of the glow.

You can correct the situation by increasing the filter smoothing factor. Since a constant voltage is applied to the LEDs, the capacitor Cd can be connected to the circuit in parallel with the smoothing capacitor C1.

Even in middle-class lamps, the LED lamp power supply is a full-fledged driver with an integrated current stabilizer (it is most often implemented using a pulse-width modulation scheme).

Availability of dimmers

Initially , a dimmer (an electronic device that allows you to adjust the power / brightness of LEDs) was developed to work with incandescent lamps. It does not work well with many models of LED lamps.

The reason for the technical conflict is the minimum load power. The dimmer is rated at approximately 50 watts, which is significantly more than most LED fixtures.

Often, when the lamps are turned on through a dimmer, flicker appears, which may disappear when the power is increased. Turning off the dimmer helps to get rid of flicker. Sometimes it is enough not to put the device toggle switch in extreme positions, or you can switch the device from the leading edge to the rear.

Poor lamp quality

The blinking of LED lamps can be visible or invisible to the human eye. The cause of the problem is a poor LED power supply, unable to qualitatively smooth the rectified mains voltage.

Excessively strong pulsations are harmful to vision if such an effect is observed daily. Manufacturers of LED lamps are required to indicate the ripple factor on their products. In Russia, this parameter is regulated by SanPiN. In Chinese lamps, it is higher than the declared values.

It is possible to change the technical parameters of Chinese lamps, but it is difficult. Usually you have to open their base and change the smoothing capacitor to a more capacious one. The main thing is that it fits in the basement.

Why does the LED lamp flash when the light is off?

LED lamps have a very low inertia. Because of this, even small pulsed currents passing through the LEDs cause the lamp to turn on for a short time, which visually resembles a flash.

The reasons for flickering in the off state are different, but they all have a common point – the current in the LEDs is supplied through circuits that are not intended for this.

Wiring problems

If the lamp flickers after the light has turned off, find out where the phase is connected from the distribution block: to the relay contacts or to the LEDs themselves. The first option is correct. If a phase is connected to a lamp that will be at constant potential, this will cause flickering.

An indicator screwdriver helps to determine the phase and zero: the light turns on when it touches the phase. If the wires are connected correctly, and the lamp is still flashing, find out if there is any induced voltage in the network.

The appearance of electricity on a wire that is disconnected from the power supply occurs if another cable connected to the mains is placed next to it. Wires can be placed in the wall. If the lamp is controlled by a conventional switch, without illumination, you may need to change the wiring.

Incorrect separation of power cables

It happens that when laying home electrical wiring, cables are laid in one strobe for the sake of economy, while according to the rules they should be laid in different channels. How incorrect cabling affects lamp flicker:

  • Due to electromagnetic interference between electrical circuits, when powerful consumers are connected, a current is induced in a cable connected to a voltage source.
  • It happens that the induced current is enough to charge the driver capacitors and turn on the LED lamp for a short time. Parasitic current increases if the load distorts the sinusoidal AC voltage. This explains why LED lamps are sometimes lit when the lights are off.

The described situation is typical for budget household appliances equipped with switching power supplies with an insufficient level of decoupling of their internal circuits.

Connection errors

The figure below shows a typical case of improper switching on of lighting circuits, leading to flickering of lamps:

Wiring causing the LED light to flash

The initial reason for its appearance is the use of cheap wires with the same insulation color, among which it is difficult to determine the phase and zero.

Another cause of the problem is non-compliance with the provision for connecting the phase wire to the switch, which is presented on the right side of the figure. Often even electricians do not comply with this rule, since when using incandescent lamps, its violation does not cause any negative consequences.

If LED bulbs are used for lighting , the error leads to the fact that they always have a phase. Leakage microcurrents, which are present even in good wiring, the driver capacitors are gradually charged, and the lamp turns on for a short time.

The presence of a light in the switch

Today, illuminated switches are very popular. They are easy to find in the dark thanks to the glow of the LED built into the key.

By shunting the switch, a permanently closed circuit is created. Even insignificant currents passing through the circuit can charge the dimmer capacitor, which, when discharged to the lamp, causes it to turn on for a short time.

The easiest way to get rid of flicker is to turn it off. To solve the problem, you do not need to purchase additional components, just interrupt (cut off) the contact between the backlight and the lamp. The flickering will disappear, but the backlight will also be deactivated.

Poor quality lamps

High-quality LED lamps are quite expensive. Many users prefer to buy cheap counterparts. Their downside is low quality. During operation, these lamps may flash.

The reason for the flickering of low-quality lamps is small capacitors. They are used in budget products. The capacitor is charged through the diodes, as a result of which flicker appears.

Installing a high-quality element with a driver that prevents flashing helps to correct the situation. The latter does not let the backlight current to the LED lamps.

Why is LED blinking dangerous?

Too much flickering of LED lamps adversely affects human health and causes many negative consequences. How flickering affects the body:

  • causes anxiety;
  • negatively affects mood;
  • provokes discomfort and dryness in the eyes;
  • causes a breakdown and deterioration in performance;
  • reduces concentration;
  • increases fatigue;
  • provokes insomnia.

How to find the cause of the problem?

Start searching for the cause of the flicker by checking the phase – whether this wire is connected correctly. It must be connected to one of the switch contacts.

If you find out that electric current is being supplied to the backlight, this is the reason for the blinking. You can check the circuit with an indicator screwdriver – this manipulation can be performed by anyone.

If the problem persists:

  • change the switch to an analog without backlight;
  • put a small power resistance;
  • use an incandescent lamp.

If the flickering reappears, inspect the wiring for damaged insulation, oxidized contacts, closely spaced cables, etc.

If flickering appears in the on position of the switch, check the stability of the voltage. If the parameters are correct, replace the LED lamp with a high-quality analogue.

Replacing the LED Bulb

What should I do if the LED lamp flickers?

The flickering problem can be solved in several ways. All work described below, leading to troubleshooting, must be performed by a professional electrician. Independent attempts to make changes to the electrical circuits can lead to a short circuit.

Disable diode

Cheap lamps do not have anti-flicker devices when off. Before turning off the diode in the switch, prepare a set of tools:

  • Phillips screwdriver;
  • pliers;
  • wire cutters;
  • voltage meter.

Work order:

  1. Before disconnecting the diode, de-energize the machine to protect yourself from electric shock.
  2. Measure the voltage across the contacts with a multimeter.
  3. Remove the illuminated switch. Remove the pads by pulling them down a little.
  4. Unscrew the screws securing the switch and antennae. Cut the required wire with wire cutters.

Separate neutral wire

The flickering problem is solved simply if the neutral and phase wires are connected to the switch at the same time. Connect a light to them. Such a rigid connection scheme causes the indicator to be constantly on, but the LED lamp stops blinking.

Increasing the capacity of the equalizing capacitor

The LED lamp power supply, installed after the input transformer or voltage divider, is used to rectify the alternating signal by means of capacitor C, which smooths out the ripples.

To reduce the effect of ripple on the quality of the rectified signal, increase the value of the equalizing capacitor. To this end, in parallel with the latter, connect a second capacitor – C1.

There is another solution to the problem – to change the capacitor to another one with a higher capacity. The latter is limited only by the dimensions of the base – the main thing is that the new capacitor fits in it.

Current limiting current-quenching resistor

The inclusion of an additional resistor R1 in the series LED circuit leads to a decrease in power consumption and load current. This reduces the intensity of their glow and smoothes out the ripples.

How to reduce LED pulsation:

  1. Reduce the current passing through the HL1-HLn circuit by 25-30%. Measure the voltage drop in the working circuit and do a little calculation.
  2. The current passing through the LEDs is determined according to Ohm’s law. Knowing the voltage and resistance R \u003d 1 kOhm, the current I \u003d U / R is easily determined.
  3. Having found the current value, reduce it by about 25% and calculate the total resistance using the same formula R=U/I. Subtract the initial resistance from the found value and get the desired value R1.
  4. Select the resistance according to the allowable power. This prevents overheating of the structure, which can lead to its complete combustion.

The above method cannot completely eliminate flashing, but it significantly reduces it.

Burning LED bulbs

Connecting homemade filters

Connecting capacitors and chokes can effectively smooth out high-frequency noise coming from the mains to the LED lamp power supply. For the simplest drivers, this solution is enough to eliminate flicker.

Features of the filter:

  1. Such a filter is assembled as a separate module, and then turned on right in front of the lamp.
  2. The filter can not be built into the base of the LED lamp. It is carried out in a dielectric case. It can be installed anywhere, but it is recommended to mount it directly in front of the cartridge.

When should you call an electrician?

You do not need to call an electrician to replace the LED lamp. But, if you cannot find the cause of the lamp flickering on your own, you will have to invite him.

He will check the connection, determine the quality of the wiring, carry out all the necessary work that requires professional skills and a certain tolerance group.

The flickering of LED lamps is a serious problem for both comfort and human health. It is important to find out the cause of the problem and fix it as soon as possible. To prevent the flickering of lamps in the house, the installation of high-quality products and serviceable wiring helps.

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